1. Field of the Invention
The present invention relates to high-frequency amplifiers, and more particularly to a high-frequency amplifier having a gain and noise figure which are stable against ambient temperature changes and suitable for mass production with a high power-consumption efficiency.
2. Description of the Related Art
Conventionally, low-noise amplifiers have been used in the input circuit of the receiving section in communication equipment or the like. Since a field effect transistor (hereinafter called FET) using gallium arsenide has a superior noise figure, it has been used as an amplifier device suitable for creating a low-noise amplifier. Although an FET is very useful as an amplifier device, it is less easy-to-use than a bipolar transistor or other alternative devices when used in communication equipment, especially in a handy, portable unit such as a portable telephone. Such a drawback will be described later in detail by referring to drawings.